Loss-of-function variants in ciliary genes confer high risk for Tetralogy of Fallot [RNA-Seq]

Tetralogy of Fallot (TOF), the most common severe cyanotic congenital heart disease, has poorly understood genetic causes. Through next-generation sequencing in 131 nonsyndromic TOF patients, we identified an increased burden of rare deleterious variants in ciliary genes and cilium pathway, and observed a multigenic inheritance pattern, with an OR of 1.672 for more than two deleterious variants and a cumulative OR of 3.158 for six variants. Functional validation in single- and double-heterozygous mouse models carrying these variants recapitulated TOF-like phenotypes and impaired normal cilia structure and function, particularly disrupting Hedgehog signaling in cardiomyocytes, downregulating key transcription factors Gata4 and Nkx2-5.